First, I would argue that this question is based in some ways on a misunderstanding of what it means to say that our republic was founded on the basis of the idea that “all men are created equal.”  Clearly, when Thomas Jefferson wrote those words, and his fellow founders signed their names to the ideas of the Declaration, they were not saying that they believed that all men really were equal.  Men like Jefferson owned slaves and believed as a matter of course that they were superior to their slaves and all other black people.  In other words, our republic was founded on the idea that all white men were created equal, not that all men of all races were created equal.  Once we think of the founding of our country in this way, the treatment of Asian immigrants is no longer incompatible with our founders’ principles.  It was perfectly logical to treat Asians as inferior in a country in which whites were assumed to be racially superior.

Because of these ideas, various laws and legal decisions arose which shaped Asian communities before WWII.  For the most part, these laws shaped Asian communities by constraining what they could do and preventing them from assimilating into American society.  These laws helped to maintain Asian cultural distinctiveness because they prevented Asians from aspiring to become American.

Let us look at two such laws or legal decisions as examples of this dynamic.  First, there was the case of Gong Lum v. Rice.  In this case, the Supreme Court of the United States held that it was legal to require Asian children to attend separate schools from those attended by white children.  Second, there were laws in various states banning marriages between Asians and whites. 

In both of these examples, the major impact was to separate whites and Asians.  When the two races were separated, Asians were forced to remain as a separate cultural group.  They could not integrate into mainstream American society.  This was the main way in which these racially-based laws and decisions shaped Asian communities, reinforcing the idea that America was a republic in which only white men were created equal to one another.